As a gemologist, you really won't get much money by just posting it somewhere, like on the of the lapidary or fossil sites. If you are really interested in getting as much as you can for the fossil, you need to take it to Tuscon for the Gem and Mineral show in February. This is where many museums and collectors will go to drop thousands and maybe millions on specimens, but the price you get will depend on the rarity of your particular specimen, and as a whole fossil, it "might" be worth something significant (MIGHT). I cannot price your piece, because fossils are not my area (and pictures are not the best way to do it anyways), but I would urge you to look up your local gemological society and ask them. Many areas will also have local gem and mineral shows, which is a good place to at least unload it for something.
I hope that helps.